An assembly by the so-called “flip-chip” technique usually comprises forming electrically-conductive bumps on a surface of a first electronic component and forming electrically-conductive connection elements, particularly bumps or connection areas, on a surface of a second component according to a predetermined connection pattern. The first component is then transferred onto the second component to place the bumps in correspondence with the connection elements, after which the assembly is pressed and heated. The bumps then deform and melt to form electric connections perpendicular to the main plane of the electronic component, generally in the form of a wafer.
The most conventional technique to form the assembly is to perform a general heating of the assembly, for example, by placing the two components under a temperature-controlled atmosphere.
However, the melting of a metal bump requires high temperatures, typically higher than 156° C. Now, such temperatures are not compatible with organic components, particularly plastic components such as PEN (polyethylene naphthalate) and PET (polyethylene terephthalate), which have glass transition temperatures lower than these temperatures, respectively of 120° C. for PEN and 70° C. for PET, for example. Thus, when submitting a plastic component to the solder bump melting temperature, the plastic component takes a rubbery state and strongly deforms, or is even destroyed.
Methods implementing a local heating of the metal bumps are also known. For example, U.S. Pat. No. 7,810,701 describes a component comprising contacts in the form of resilient spirals covered with a resistive layer having the bumps deposited thereon. By circulating a high-frequency electric current in the spirals, an electromagnetic field which causes the melting of the resistive layer and of the bumps is created. This method is thus irreversible and does not enable to separate the two hybridized components without causing their destruction.